The present invention relates to an arrangement e.g. for image generation and/or reading which comprises in substantially two dimensions arranged first and second light elements and controlling and addressing means for activating light or picture elements. The first light or picture elements are real and form a thin matrix. The second elements are also real and form a matrix which is denser.
The invention further relates to a display and to a detecting arrangement for reading images.
Devices are known in the form of a display or even in the form of arrangements for e.g. optical, magnetical or electrical reading. In some applications it can be required or be desirable to have e.g. a display which has a very small total area but wherein the number of picture- or light elements however is very high, e.g. a display in the form of a matrix with for example 1000.times.1000 light elements on a surface which may be 1 cm.sup.2 or even smaller. Since all light elements, for example liquid crystal elements, require individual addressing and feeding etc. it is very hard to produce a similar matrix due to the difficulties in achieving individual addressing, feeding etc. to all the elements on such a small area. Generally the problems are the same for devices for image generation as well as for reading and the difficulties in addressing, feeding etc. are similar independently of whether it is question about an arrangement of the one or the other kind.
In a number of known arrangements linear arrangements or "arrays" are used, such as light elements or sources arranged in one or more rows which are swept so that a matrix is formed. If the total area of the matrix formed is to be very small and at the same time the number of light elements is to be high, the linearly arranged which is light elements must be very densely arranged why the addressing gets very difficult. Furthermore the linear device of light elements or light sources has to be moved or swept a comparatively long distance which is a considerable drawback. This in turn leads to that the sweep also has to take place with a comparatively high speed.
If for example it is needed to move a display in the form of a matrix of e.g. 1000.times.1000 liquid crystal elements and the surface has to be smaller than 1 cm.sup.2, which may be necessary in a number of applications, a pixel size of 10.times.10 .mu.m or smaller is obtained, which as mentioned above is very difficult, if possible at all, to achieve depending on addressing and feeding problems etc.
An example of a linear arrangement as referred to above is shown in U.S. Pat. No. 4,225,862. In this document a display unit comprises a number of light sources, for example LEDs, which are arranged linearly. The light sources which are arranged in a row are oscillated vertically, i.e. in one direction or in one dimension, in order to provide a display. According to this document it is also possible to arrange the light sources in a number of parallel rows. Also in this case the light elements are closely arranged and oscillate or are swept merely in one dimension or in one direction. Therethrough also in this case the distance that the spots are moved will be long.
In U.S. Pat. No. 4,934,773 a miniature-video-display is disclosed which comprises light emitting elements arranged in at least one row, an amplifying lens and a vibrating mirror. The light elements (LED) are illuminated selectively at different points during the translation of the vibrating mirror wherethrough rows of pixels are projected on selected spots of the mirror so that a two dimensional image is obtained. According to this document the light emitting elements may also be arranged in two or more rows. The intention therewith is that those should have different colours so that a colour image can be provided. This document also describes an arrangement in combination with an optical system wherein the sweep not is real but achieved in an optical way. Also in this case, if a small display with a high resolution is required, must therefore the light elements be very closely arranged which is problematic depending on difficulties in physically arranging and mounting as well as in addressing and feeding the closely arranged light elements.